nrhythmthe basic rhythmic unit in a piece of music"the piece has a fast rhythm","the conductor set the beat"

nrhythman interval during which a recurring sequence of events occurs"the never-ending cycle of the seasons"

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Webster's Revised Unabridged Dictionary

Interesting fact:
Jazz began in the 20th century, when bands in New Orleans began to apply the syncopated rhythms of ragtime to a variety of other tunes. In the first days of jazz, ensemble playing was emphasized. Only gradually did jazz come to be based on improvised solos.

RhythmA division of lines into short portions by a regular succession of arses and theses, or percussions and remissions of voice on words or syllables.

RhythmIn the widest sense, a dividing into short portions by a regular succession of motions, impulses, sounds, accents, etc., producing an agreeable effect, as in music poetry, the dance, or the like.

Rhythm(Mus) Movement in musical time, with periodical recurrence of accent; the measured beat or pulse which marks the character and expression of the music; symmetry of movement and accent.

RhythmThe harmonious flow of vocal sounds.

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Century Dictionary and Cyclopedia

nrhythmMovement in time, characterized by equality of measures and by alternation of tension (stress) and relaxation. The word rhythm (ῤυθμός) means ‘flow,’ and, by development from this sense, ‘uniform movement, perceptible as such, and accordingly divisible into measures, the measures marked by the recurrence of stress.’ Examples of rhythm, in its stricter sense, in nature are respiration and the beating of the pulse, also the effect produced on the ear by the steady dripping of water. The three arts regulated by rhythm are music, metrics, and, according to the ancients, orchestic, or the art of rhythmical bodily movement. Rhythm in language is meter. The term was further extended to sculpture, etc. (compare def. 5), as when a writer speaks of “the rhythm of Myron's Discobolus.”

nrhythmIn music: That characteristic of all composition which depends on the regular succession of relatively heavy and light accents, beats, or pulses; accentual structure in the abstract. Strictly speaking, the organic partition of a piece into equal measures, and also the distribution of long and short tones within measures, in addition to the formation of larger divisions, like phrases, sections, etc., are matters of meter, because they have to do primarily with time-values; while everything that concerns accent and accentual groups is more fitly arranged under rhythm. But this distinction is often ignored or denied, meter and rhythm being used either indiscriminately, or even in exactly the reverse sense to the above. (See meter.) In any case, in musical analysis, rhythm and meter are coördinate with melody and harmony in the abstract sense.

nrhythmA particular accentual pattern typical of all the measures of a given piece or movement. Such patterns or rhythms are made up of accents, beats, or pulses of equal duration, but of different dynamic importance. A rhythm of two beats to the measure is often called a two-part rhythm; one of three beats, a three-part rhythm, etc. Almost all rhythms may be reduced to two principal kinds: duple or two-part, consisting of a heavy accent or beat and a light one (often called march rhythm or common time); and triple or three-part, consisting of a heavy accent or beat and two light ones (waltz rhythm). The accent or beat with which a rhythm begins is called the primary accent. Its place is marked in written music by a bar, and in conducting by a down-beat. Each part of a rhythm may be made compound by subdivision into two or three secondary parts, which form duple or triple groups within themselves. Thus, if each part of a duple rhythm is replaced by duple secondary groups, a four-part or quadruple rhythm is produced, or if by triple secondary groups, a six-part or sextuple rhythm (first variety). By a similar process of replacement, from a triple rhythm may be derived a six-part or sextuple rhythm (second variety) and a nine-part or nonuple rhythm; and from a quadruple rhythm, an eight-part or octuple rhythm and a twelve-part or dodecuple rhythm. The constituent groups of compound rhythms always retain the relative importance of the simple part from which they are derived. The above eight rhythms are all that are ordinarily used, though quintuple, septuple, decuple, and other rhythms occasionally appear, usually in isolated groups of tones. (See quintuplet, septuplet, decimole, etc.) In ancient music a measure did not necessarily begin with a beat, and the rhythms were the same as those indicated in metrics below (3 ). While all music is constructed on these patterns, the pattern is not always shown in the tones or chords as sounded. The time-value of one or more parts may be supplied by a silence or rest. A single tone or chord may be made to include two or more parts, especially in compound rhythms; and thus every possible combination of long and short tones occurs within each rhythm. When a weak accent is thus made to coalesce with a following heavier one, especially if the latter is a primary accent, the rhythm is syncopated. (See syncopation.) The regularity of a rhythm is maintained by counting or beating time—that is, marking each part by a word or motion, with a suitable difference of emphasis between the heavy and the light accents. In written music the rhythm of a piece or movement is indicated at the outset by the rhythmical signature (which see, under rhythmical). The speed of a rhythm in a given case—that is, the time-value assigned to each measure and part—is called its tempo (which see). Rhythm and tempo are wholly independent in the abstract, but the tempo of a given piece is approximately fixed. Although regularity and definiteness of rhythm are characteristic of all music, various influences tend to modify and obliterate its form. The metrical patterns of successive measures often differ widely from the typical rhythmic pattern and from each other. Except in very rudimentary music, purely rhythmic accents are constantly superseded by accents belonging to figures and phrases—that is, to units of higher degree than measures. Indeed, in advancing from rudimentary to highly artistic music, rhythmic patterns become less and less apparent, though furnishing everywhere a firm and continuous accentual groundwork. Rhythm is often loosely called time. Also called proportion.

nrhythmIn metrics: Succession of times divisible into measures with theses and arses; metrical movement. Theoretically, all spoken language possesses rhythm, but the name is distinctively given to that which is not too complicated to be easily perceived as such. Rhythm, so limited, is indispensable in metrical composition, but is regarded as inappropriate in prose, except in elevated style and in oratory, and even in these only in the way of vague suggestion, unless in certain passages of special character.

nrhythmA particular kind or variety of metrical movement, expressed by a succession of a particular kind or variety of feet: as, iambic rhythm; dactylic rhythm. In ancient metrics, rhythm is isorrhythmic, direct, or dochmiac (see the phrases below), or belongs to a subdivision of these.

nrhythmA measure or foot.

nrhythmVerse, as opposed to prose. See rime.

nrhythmIn physics and physiology, succession of alternate and opposite or correlative states.

nrhythmIn the graphic and plastic arts, a proper relation and interdependence of parts with reference to each other and to an artistic whole.

nrhythmSynonyms Melody, Harmony, etc. See euphony.

nrhythmA rhythm produced by alternations of clang-tint—in the simplest case, by compound tones alike in duration, pitch, and energy, but different in tint (as proceeding from different instruments, or sung by different voices).

nrhythmIn music: Same as duple rhythm.

nrhythmA rhythm with only two or three beats to the measure: opposed to compound rhythm or time. See compound measure.

So, Wayne Shorter remembers how he'd step up to the mic and the rhythm section — that's Herbie Hancock on piano, Ron Carter on bass, Tony Williams on drums — would mostly or even almost wholly drop out, leaving him hanging, as we say today.